Greetings Russellje,
Welcome to Apple Support Communities. What you are experiencing is a normal part of the flow that protects sensitive data, like passwords, credit card numbers, and Messages stored in iCloud. After entering your Apple ID, password, and passcode on the new device, you may get a prompt to approve from another device. If so, check for an approval notification on all other devices that you are signed in to iCloud on. Tap Allow, and then enter your Apple ID password on the device. At this point, you might see a warning that says "Can’t Approve". If so, you might need to reset the existing data on your account if you want to continue to store your encrypted data in iCloud. Resetting the data is a security requirement to protect the your privacy and keep the most sensitive data secured. You would need to reset the passcode on both devices to retain access to your personal data. The steps to do so without using a computer are found in the Apple Support article: If you see an iPhone or iPad unavailable message or Security Lockout screen
How to reset your device
If you're using an eSIM, contact your carrier before trying these steps and ask for a QR code to set up your eSIM again.
1.From your device's Lock Screen, try to enter your passcode five times until the "[Device] Unavailable" screen appears and your device asks you to try again later.
2.When you're able to, continue to enter your passcode until the "Security Lockout" screen appears and you get the Erase [Device] option in the bottom corner of the screen.
3.Tap Erase [Device], then tap Erase [Device] again to confirm.
4.Enter your Apple ID password to sign out of your Apple ID on your device.
5.Tap Erase [Device] to permanently delete all of your data and settings.
6.When your device restarts, follow the onscreen instructions to set up your device again, restore your data and settings from a backup, and set a new passcode.
Feel free to reach back out if you have any questions.
Best regards!
